For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:lnussel:branches:systemsmanagement:cockpit/openSUSE_Tumbleweed/home:lnussel:branches:systemsmanagement:cockpit.repo
zypper refresh
zypper install selinux-policy
For openSUSE Factory run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:lnussel:branches:systemsmanagement:cockpit/openSUSE_Factory/home:lnussel:branches:systemsmanagement:cockpit.repo
zypper refresh
zypper install selinux-policy